Many motorized pumps include bearings housed in bearing boxes. The bearings allow for the low friction spinning of the pump shaft driven by a motor. Oil is circulated within bearing box to lubricate the bearings and shaft as it spins. The bearings on the shaft of a bearing box generate heat dependent on many factors including the amount of load they experience. For bearings that are lubricated through a pressure lube system, which is a self-contained system that circulates oil through a bearing box, the oil absorbs the heat and transfers it away. That heat needs to be removed from the assembly in some fashion. Typically, this is done by circulating the oil through a water cooled heat exchanger or using a fan to blow air past the bearing box itself and allowing the heat to conduct through the bearing box before being dissipated to the surrounding air.
Unfortunately, the water cooled heat exchanger solution requires a cold water supply, which is often not available or more expensive to pipe into the area. In addition, relying on conduction through the bearing box develops a significant temperature difference between the oil and the outside of the bearing box, which decreases the heat transfer capability drastically. If the bearings generate any significant amount of heat, the oil quickly reaches and goes beyond its max working temperature. Another cooling method may include an oil-to-air heat exchanger external to the pump with an electric motor driven fan or relying on natural convection. However, in hazardous environments, the fins on these types of heat exchangers can become damaged very easily in addition to the need to provide power for any fan used. Therefore, it was determined to look at utilizing air cooling to remove the need for any additional resources, while minimizing the temperature gradient between the oil and the external heat transfer surface area.